Insect Pest Of Rice Research Articles

Seleção de fungos entomopatogênicos para controle de percevejos e bicudo-do-algodoeiro

ABSTRACT Entomopathogenic fungi stand out in the biological control of several agriculturally important insects. Six isolates of Metarhizium anisopliae, Cordyceps javanica, Beauveria sp. and B. bassiana were screened to control Anthonomus grandis, Euschistus heros, Oebalus poecilus, O. ypsilongriseus and Thyanta perditor, important insect pests of soybean, cotton and rice. The bioassays were conducted in a completely randomized design, with four replications (10 insects/replication). Significant differences for virulence were observed between the tested fungal species and isolates. For A. grandis, the most virulent isolate was M. anisopliae BRM 2335, followed by Beauveria BRM 14527 and BRM 67744 [82.5 to 97.5 % of mortality; average lethal time (LT50) of 5.9 to 7.8 days]. M. anisopliae BRM 2335 was also highly virulent to the four stink bug species (75 to 97.5 % of mortality; LT50 of 5.2 to 9.7 days). For the stink bugs, Beauveria sp. BRM 67744 was infectious to O. poecilus (75 % of mortality), but failed to control E. heros (16.9 % of mortality). C. javanica BRM 27666 and BRM 14526 showed average virulence to the stink bugs and A. grandis (17.5 to 57.3 % of mortality; LT50 of 6.0 to 9.7 days). M. anisopliae was consistently more virulent to the stink bugs than the other fungi. Therefore, M. anisopliae BRM 2335 was selected for further studies under screenhouse and field conditions to control A. grandis and other stink bug species, especially E. heros.

Population dynamics of major insect pests of rice and the impact of climatic factors on their population

Population dynamics of major insect pests of rice and the impact of climatic factors on their population

Farmers’ Perception of Plant Protection Practices and Management of Insect Pests of Rice in Lahore Division, Pakistan

Farmers’ Perception of Plant Protection Practices and Management of Insect Pests of Rice in Lahore Division, Pakistan

Validation of integrated pest management tools against Lepidopterous insect pest of rice

Validation of integrated pest management tools against Lepidopterous insect pest of rice

Seasonal incidence of gall midge, Orseolia oryzae (Wood-Mason), a major insect pest of rice and its reaction on various rice germplasm

Seasonal incidence of gall midge, Orseolia oryzae (Wood-Mason), a major insect pest of rice and its reaction on various rice germplasm

SEASONAL INCIDENCE OF MAJOR INSECT PESTS OF RICE IN KRISHNA WESTERN DELTA REGION OF GUNTUR DISTRICT

The seasonal occurrence of major insect pests of rice in Guntur district of Andhra Pradesh during kharif 2021-22 was studied in Krishna Western Delta area in 90 farmers fields of 10 mandals (Bapatla, Kakumanu, Ponnur, Tsunduru, Amruthaluru, Vemuru, Tenali, Duggirala, Repalle and Nagaram). Fortnightly observations on pest population in parallel relation with meteorological parameters revealed the highest leaf damage due to rice leaf folder Marasmia medinalis (Crambidae: Lepidoptera)during second fortnight of September (2.95%) when the crop was more succulent. The incidence of yellow stem borer Scirpophaga incertulas (Crambidae: Lepidoptera) begun appearing during first fortnight of August with highest percent damage during second fortnight of September causing 2.62 percent dead hearts. The peak population of brown planthopper Nilaparvata lugens (Delphacidae: Hemiptera) was observed during first fortnight of October (4.97 hoppers/hill) when the crop was in panicle initiation stage.

Pest-Defender Abundance under Evaluation of Ecofriendly Insecticides against Major Insect Pests of Rice in Eastern Uttar Pradesh Conditions

The present study was analyzed the abundance of pest: defender ratio (P:D) over check plot under evaluation of ecofriendly insecticides against the major insect pests of rice in eastern Uttar Pradesh conditions for two consecutive years (2014 and 2015) at farmer field of district Deoria under the supervision of Department of Entomology, B.R.D.P.G. College, Deoria, Uttar Pradesh, India. There were 10 treatments (09 insecticides + 01 check) evaluated under randomized block design (RBD) by transplanting method of rice cultivation on localized popular rice cultivar Samba Mahsuri (BPT-5204). The insecticide treatments comprise 9 insecticides (CartapHcl, 50 SP, Indoxacarb 14.5 SC, Imidacloprid 17.8 SL, Chlorpyriphos 20 EC, Thiamethoxam 25 WG, Chlorantraniliprole 18.5 SC, Azadirachtin (Neem Oil) 0.03 EC, Bacillus thuringiensis kurstaki (Btk) 3.5 WP, and combination of Neem Oil 0.03 EC + Btk 3.5 WP).This evaluation was observed most effective ecofriendly insecticides concerned to lowest pest: defender ratio (P:D), lowest abundance of pest: defender ratio (P:D) over check plot, and highest yield. The inferences of pest: defender abundance ratio (P:D) over check plot and yield of rice crop were based on non-significant ecofriendly insecticides for the lowest pest: defender ratio (P:D). There were 2 insecticides (Neem Oil + Btk and Imidacloprid) inference non-significant for the lowest abundance of pest: defender ratio (P:D) over check plot. The mean ranking and inference of abundance of pest: defender ratio (P:D) over check was similar to the inference of non-significant ecofriendly insecticides for lowest pest: defender ratio (P:D) as, Neem Oil + Btk and Imidacloprid respectively.

Infestation Suppression under Evaluation of Ecofriendly Insecticides against Major Insect Pests of Rice in Eastern Uttar Pradesh Conditions

The present study was undertaken to analysis the suppression of infestation over check plot under evaluation of ecofriendly insecticides against major insect pests of rice in eastern Uttar Pradesh conditions for the two consecutive years (2014 and 2015) at farmer field of district Deoria under the supervision of Department of Entomology, B.R.D.P.G. College, Deoria, Uttar Pradesh, India. There were 10 treatments (09 insecticides + 01 check) evaluated under randomized block design (RBD) by transplanting method of rice cultivation on localized popular rice cultivar Samba Mahsuri (BPT-5204). The insecticide treatments comprise 9 insecticides (CartapHcl, 50 SP, Indoxacarb 14.5 SC, Imidacloprid 17.8 SL, Chlorpyriphos 20 EC, Thiamethoxam 25 WG, Chlorantraniliprole 18.5 SC, Azadirachtin (Neem Oil) 0.03 EC, Bacillus thuringiensis kurstaki (Btk) 3.5 WP, and combination of Neem Oil 0.03 EC + Btk 3.5 WP). This evaluation was observed most effective ecofriendly insecticides concerned to lowest infestation, highest suppression of infestation over check plot, and highest yield. The inferences of suppression over check plot and yield of rice crop were based on non-significant ecofriendly insecticides for lowest infestation. There were 2 insecticides (CartapHcl and Imidacloprid) inference non-significant for highest suppression of infestation over check. There were 3 insecticides (CartapHcl, Imidacloprid, and Neem Oil + Btk) inference non-significant for lowest infestation and highest yield respectively. The mean ranking and inference of suppression over check were similar to inference of non-significant ecofriendly insecticides for lowest infestation as, Imidacloprid, CartapHcl, and Neem Oil + Btk respectively.

Occurrence of Entomopathogenic Fungi from Natural Ecosystems in Phetchabun, Thailand and Their Virulence Against Brown Planthopper

Brown planthopper (BPH), Nilaparvata lugens Stål, is a serious insect pest of rice. The invasion of BPH causes heavy losses in rice production, both quality and quantity. The objective of this research was to search for Metarhizium spp., a genus of entomopathogenic fungi in the Clavicipitaceae family, from forest soil in three districts of Phetchabun Province, Thailand: Khao Kho, Lom Kao and Nam Nao to control BPH. Metarhizium spp. fungi were isolated by soil dilution plate technique and determined their efficacy using conidia suspension at the concentration of 1X108 conidia/mL on BPH at the 2-3th instar nymph fed on seedlings of susceptible rice cultivars, Taichung Native 1 (TN1). The most effective Metarhizium sp. isolate was identified using the ITS region of 18S rDNA sequencing, Basic Local Alignment Search Tool (BLAST) and evolutionary history. The result showed that 126 isolates of Metarhizium spp. were found and coded as PB-01 to PB-126. All isolates infected BPH nymph with 26.7 to 100% mortality within 6 days after contacting conidia suspension. The isolate of PB-75 showed the highest efficacy (100% BPH mortality) with the lethal times of 50% mortality (LT50) within 2.9 days. The species identification showed that the DNA sequence of Metarhizium sp. isolate, PB-75, was 98.6% similar to M. anisopliae Genbank ID JQ889704.1. Evolutionary history based on phylogenetic analysis using neighbor-joining and maximum parsimony methods confirmed that PB-75 formed the same phylogenetic clade with M. anisopliae Genbank ID JQ889704.1 and M. anisopliae var. anisopliae.

Analysis of the Feeding Behavior and Life Table of Nilaparvata lugens and Sogatella furcifera (Hemiptera: Delphacidae) under Sublethal Concentrations of Imidacloprid and Sulfoxaflor

The brown planthopper (BPH) Nilaparvata lugens and white-backed planthopper (WBPH) Sogatella furcifera are serious rice insect pests that cannot overwinter in Korea and migrate from southeast Asian countries and China. In this study, we investigated the sublethal effects of imidacloprid and sulfoxaflor on the biological parameters and feeding behavior of planthoppers. These sublethal concentrations significantly decreased the net reproduction rate (R0), the intrinsic rate of increase (rm), and the mean generation time (T). For BPHs, the total durations of nonpenetration (NP) waveform by imidacloprid (LC10 = 164.74 and LC30 = 176.48 min) and sulfoxaflor (LC10 = 235.57 and LC30 = 226.93 min) were significantly different from those in the control group (52.73 min). In addition, on WBPHs, the total durations of NP waveform by imidacloprid (LC10 = 203.69 and LC30 = 169.9 min) and sulfoxaflor (LC10 = 134.02 and LC30 = 252.14 min) were significantly different from those in the control group (45.18 min). Moreover, the LC10 and LC30 of these insecticides significantly decreased the phloem feeding time. In conclusion, imidacloprid had a better effect on the inhibition of feeding of the WBPH, and sulfoxaflor showed a better effect on the inhibition of feeding of the BPH. Therefore, it is suggested that treatment with sublethal concentrations of the above insecticides will reduce the feeding of BPHs and WBPHs on rice phloem.

Genome-wide identification of FAR gene family and functional analysis of NlFAR10 during embryogenesis in the brown planthopper Nilaparvata lugens

Fatty acyl-CoA reductases (FARs) catalyze the synthesis of fatty alcohols from corresponding fatty acid precursors in organisms. However, the function of FARs in insect fecundity and embryogenesis remains largely unclear. Here, a total of 22 putative FAR proteins were identified in the brown planthopper Nilaparvata lugens, a hemipteran insect pest of rice, and most of them were highly expressed in embryonic stages. Among them, NlFAR10 was specifically and highly expressed in the later embryogenesis, but was promiscuously expressed in tissues of adults. The heterologously expressed NlFAR10 was able to produce the intermediate fatty acid alcohols from the corresponding acyl-CoA precursors. When NlFAR10 was silenced through RNAi in vivo, the embryogenesis was obviously inhibited, resulting in low hatching rates. Moreover, the metabolome analyses indicated that loss of NlFAR10 affected lipid metabolism and purine metabolism during embryogenesis. To the best of our knowledge, this is the first report of a FAR member affecting insect embryogenesis, thus providing a new target for future pest management.

Evaluation and characterization of indigenous rice (Oryza sativa L.) landraces resistant to brown planthopper Nilaparvata lugens (Stål.) biotype 4.

Evaluation and identification of resistant donors for brown planthopper (BPH) Nilaparvata lugens (Stål.), an economically important insect pest of rice, is a continuous process to develop new resistant rice varieties. However, several rice landraces of north-eastern India are not yet characterized for BPH resistance. In the present study, a set of 218 rice landraces were screened in both greenhouse and open-field conditions for three consecutive years, and thereafter forty selected promising entries were explored to evaluate their phenotypic and genotypic reactions against BPH biotype 4. Based on phenotypic evaluations, five landraces were identified as resistant, while 31 were moderately resistant, and grouped under the major cluster I and II, respectively, in a circular dendrogram. Antixenosis and antibiosis studies of these landraces divulged that, compared to the susceptible check variety, resistant landraces exhibited the lowest feeding rate, survival, and nymphal and adult settling, but higher frequency of unhatched eggs of BPH. Un-infested resistant landraces registered higher levels of ascorbic acid, oxalic acid and crude silica, however, elevated levels of total free amino acid, potassium and crude silica were observed under BPH herbivory. The present study focuses on identifying new donors having BPH resistance resources which could be useful in genomic studies for the development of BPH biotype 4 resistant rice varieties.

Iranian diatomaceous earth as a control agent for protection of paddy rice against Sitotroga cerealella (Oliv.) (Lepidoptera, Gelechiidae) and its delayed effects on physicochemical properties of paddy rice

Sitotroga cerealella (Oliv.) (Lepidoptera: Gelechiidae) is one of the destructive insect pests of paddy rice in grain storage facilities and warehouses. For this study, the insecticidal activity of a new Iranian DE formulation, Dryasil, was evaluated against S. cerealella fourth instar larvae on three varieties of paddy rice: Hashemi, Khazar, and Champa. The bioassays were carried out at the concentrations of 400 and 1000 mg/kg and four temperature levels (15, 20, 25, and 30 °C) after 7, and 14 d of exposure interval. The effects of this protectant were also investigated on the quality of the treated-paddy rice after three months of storage. In all tested varieties, mortality of the exposed larvae increased with increased concentration of DE and exposure period. The activity of DE was higher at 30 °C than other tested temperatures. The highest larval mortality (69.80%) was reported in Khazar variety treated with 1000 mg/kg at 30 °C. The larvae were well controlled in Khazar and then Hashemi variety. The DE had no adverse effects on water absorption rate, volume expansion ratio, cooking time, and chalkiness percentage. Overall, our findings suggest that Dryasil could be considered as a grain protectant that does not adversely affect the properties of different paddy rice varieties to control S. cerealella.

Progress in exploitation and utilization of brown planthopper resistance gene in rice

<p indent="0mm">Rice is the most important food crop globally and a model species for basic biological research. Brown planthopper (BPH) is one of the major insect pests of rice. In the past decades, scientists have explored the BPH resistance gene from rice germplasm and revealed the molecular mechanism underlying the host plant resistance of rice to BPH. Research results have promoted the development of BPH-resistant rice varieties and their release in rice production. This review briefly introduces the research progress on brown planthopper resistance gene discovery, mechanism analysis, germplasm innovation, and utilization in rice breeding programs to help readers understand the mystery of plant resistance against insects and the practical significance of insect resistance research in plants.

Field evaluation of biopesticides against rice insect pests under organic farming

Neem based commercial formulations Ecotin (azadirachtin 5%; 50,000 ppm) @ 150,175 and 200 ml ha-1, and standard checks- Achook (azadirachtin 0.15%; 1500 ppm) @ 2500 ml ha-1 were applied at pest appearance for evaluating them for the management of rice stem borers Scirpophaga spp. and leaf folder Cnaphalocrocis medinalis (Guenee) on basmati and non-basmati rice under organic cultivation conditions. In basmati, the reduction of deadhearts due to stem borers was observed to be maximum with Ecotin @ 200 ml ha-1 as 55.79 and 56.84% at 5 and 10 DAS, respectively; while white ears were at 55.99% in 2019; and reduction of deadhearts was 50.45 and 45.75% at 5 and 10 DAS, respectively, while white ears reduced up to 50.71% in 2020. Similarly, reduction of damaged leaves due to leaf folder was 55.80 and 59.62% at 5 and 10 DAS, respectively; and in 2020, it was 50.45 and 45.75% at 5 and 10 DAS, respectively. Ecotin 5% @ 200 ml ha-1 gave maximum crop yield (31.29 q ha-1). In non-basmati rice too the reduction of deadhearts was maximum with Ecotin @ 200 ml ha-1, while white ears reduced by 50.47% in 2019, with similar trend in 2020; also results were of similar trend with leaf folder. The occurrence of spiders revealed a non-significant difference among the treatments. The biopesticides caused no residual or phytotoxic effects and were safe to the environment and predatory fauna.

Effect of Insecticide Application Rates on Population Density of Orseolia oryzivora in Relation to its Parasitoids on Rice

Africa rice gall midge (Orseolia oryzivora) is a major insect pest of rice and the use of insecticides in its control poses danger to the environment and destroys biodiversity. The experiment was conducted to evaluate effect of lambda-cyhalothrin and carbofuran rates on population density of O. oryzivora in relation to its parasitoids on rice. The treatments were arranged in split-plot and fitted in to Randomized Complete Block Design, replicated three times. Observations were made on tiller number per hill, plant height, days to 50% flowering, % incidence, % severity, % parasitism of O. oryzivora, panicle /m2, grains / panicle and yield of rice. Data collected were subjected to Analysis of Variance and significant means were separated using Least Significant Difference (LSD) at p&lt;0.05. The result showed that Rice plants treated with lambda-cyhalothrin at rate of 1L/ha, 0.75 L/ha, Carbofuran at rate of 10.0 kg/ha and 7.5 kg/ha had higher yield (2.90-2.97 tonnes/ha) compared with control (2.55 tonnes/ha). They also had lowest incidence (2.09-2.64%) and severity (2.40-3.72%) of O. oryzivora compared with 8.26-17.17% and 9.93- 14.72% in plants treated with lambda-cyhalothrin at 0.50 L/ha and control respectively. The parasitism of O. oryzivora was high on rice plants treated with Carbofuran and the untreated ones (1.16-1.74) compared with other application of lambda-cyhalothrin.

Identification of Key Headspace Volatile Compounds Signaling Preference for Rice over Corn in Adult Females of the Rice Leaf Folder Cnaphalocrocis medinalis.

Volatile organic compounds are important for herbivorous insects in locating their host plants. The rice leaf folder, Cnaphalocrocis medinalis (Guenée), is a devastating migratory insect pest of rice in Asian countries. Although C. medinalis can develop even better on corn than on rice plants in insectaries, it rarely occurs on corn plants in the field. We hypothesized that plant volatile-mediated oviposition preference for rice over corn in adult females may be the reason for the observed rare field occurrence of the pest on corn plants. The present study was conducted to identify the olfactory active volatile compounds (OAVCs) that enable C. medinalis females to discriminate rice from corn plants. In cage tests, rice plants were highly preferred for oviposition over corn plants by C. medinalis females. From headspace, chemical analyses identified 15 rice unique, 8 corn unique, and 28 common volatile compounds. Fourteen OAVCs, including seven common, five rice unique, and two corn unique, were determined. In electroantennogram tests, the rice unique and common OAVCs activated the antennal responses in C. medinalis. In Y-tube olfactometer tests, (E)-2-hexenal and 3-hexanol(common OAVCs) and (Z)-3-hexenyl acetate and (E)-2-hexen-1-ol (rice unique OAVCs) attracted more C. medinalis females than the control, and only blends with both rice unique and common OAVCs were highly preferred over the control. Our results provide insights into the chemical cues used by C. medinalis adult females in host location, which may aid the development of novel crop protection strategies based on the manipulation of host-finding behaviors of C. medinalis.

Count Data Regression Models: An Application to the Major Rice Insect Pest Counts in the Terai Region of West Bengal

Count Data Regression Models: An Application to the Major Rice Insect Pest Counts in the Terai Region of West Bengal

Extrapolating potential crop damage by insect pests based on land use data: examining inter-regional generality in agricultural landscapes

BackgroundInter-regional relationships between landscape factors and biological responses in natural conditions are important but difficult to predict because of the differences in each landscape context and local environment. To examine the inter-regional variability in relation to landscape factors and the biological response of an insect pest of rice, Stenotus rubrovittatus, we extrapolated a damage prediction model (the ‘original model’ of our previous study) for rice using land-use data. The ‘original model’ comprised as fixed factors the area of source habitat (i.e. pastures and graminoid-dominated fallow fields), soybean fields, and rice paddies within 300-m radii with research years as the random intercept. We hypothesized that the original model would be applicable to new regions, but the predictive accuracy would be reduced. We predicted that fitting a new extended model, adjusting the parameter coefficients of identical fixed factors of the ‘original model,’ and adding regional random intercepts would improve model performance (the ‘extended model’). A field experiment was conducted in two regions that had a similar landscape context with the original region, each in a different year of four years in total. The proportion of rice damage and surrounding land use within a 300-m radius was investigated, and the data were applied to the models and the applicability and accuracy of the models were examined.ResultsWhen the ‘original model’ was assigned to the combined data from the original and extrapolated regions, the relationship between the observed and the predicted values was statistically significant, suggesting that there was an inter-regional common relationship. The relationship was not statistically significant if the model was applied only to the new regions. The extended model accuracy improved by 14% compared with the original model and was applicable for unknown data within the examined regions as demonstrated by three-fold cross validation.ConclusionsThese results imply that in this pest–crop system, there is likely to be a common inter-regional biological response of arthropods because of landscape factors, although we need to consider local environmental factors. We should be able to apply such relationships to identify or prevent pest hazards by offering region-wide management options.

Cytokinin Confers Brown Planthopper Resistance by Elevating Jasmonic Acid Pathway in Rice.

Plants have evolved a sophisticated defense system that employs various hormone pathways to defend against attacks by insect pests. Cytokinin (CK) plays an important role in plant growth and stress tolerance, but the role of CKs in plant–insect interaction remains largely unclear. Here, we report that CKs act as a positive regulator in rice resistance against brown planthopper (BPH), a devastating insect pest of rice. We found that BPH feeding promotes CK biosynthesis and signaling in rice. Exogenous application of CKs significantly increased the rice resistance to BPH. Increasing endogenous CKs by knocking out cytokinin oxidase/dehydrogenase (OsCKXs) led to enhanced resistance to BPH. Moreover, the levels of the plant hormone jasmonic acid (JA) and the expression of JA-responsive genes were elevated by CK treatment and in OsCKXs knockout plants. Furthermore, JA-deficient mutant og1 was more susceptible to BPH, and CK-induced BPH resistance was suppressed in og1. These results indicate that CK-mediated BPH resistance is JA-dependent. Our findings provide the direct evidence for the novel role of CK in promoting insect resistance, and demonstrate that CK-induced insect resistance is JA-dependent. These results provide important guidance for effective pest management strategies in the future.